<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        body {
            font-size: 20px;
            /* line-height: 200%; */
            /* 50px */
            line-height: 50px;
            /* 30px */
            line-height: 1.5;
            /* 40px，先算完再继承 */
            line-height: 200%;
        }

        p {
            font-size: 16px;
        }
    </style>
</head>

<body>
    <p>AAA</p>
</body>

</html>